Sidelink reference signal search

Abstract

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, periodically, at least one metric associated with a current reference signal on a sidelink. Accordingly, the UE may extend a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric. For example, the UE may extend the time window as a function of a discontinuous reception cycle associated with the UE. Alternatively, the UE may extend the time window for a preconfigured amount of time. Numerous other aspects are described.

What is claimed is: 
     
         1 . An apparatus for wireless communication at a user equipment (UE), comprising:
 a memory; and   one or more processors, coupled to the memory, configured to:
 determine, periodically, at least one metric associated with a current reference signal on a sidelink; and 
 extend a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the time window is extended as a function of a discontinuous reception (DRx) cycle associated with the UE. 
     
     
         3 . The apparatus of  claim 1 , wherein the time window is extended for a preconfigured amount of time. 
     
     
         4 . The apparatus of  claim 1 , wherein, to extend the time window, the one or more processors are configured to refrain from performing the search. 
     
     
         5 . The apparatus of  claim 1 , wherein the at least one metric comprises a reference signal received power (RSRP) associated with the current reference signal, an RSRP variation associated with the current reference signal, an RSRP trend associated with the current reference signal, a reference signal received quality (RSRQ) associated with the current reference signal, or a combination thereof. 
     
     
         6 . The apparatus of  claim 5 , wherein the one or more processors, to extend the time window, are configured to extend the time window based on:
 the RSRP associated with the current reference signal satisfying an RSRP threshold;   the RSRP variation associated with the current reference signal satisfying a variation threshold;   the RSRQ associated with the current reference signal satisfying an RSRQ threshold;   a direction of the RSRP trend associated with the current reference signal satisfying a trend threshold; or   a combination thereof.   
     
     
         7 . The apparatus of  claim 1 , wherein the one or more processors are further configured to:
 transmit to a source UE associated with the current reference signal,   wherein the one or more processors, to extend the time window, are configured to extend the time window based at least in part on a data connection with the source UE.   
     
     
         8 . The apparatus of  claim 1 , wherein the one or more processors are further configured to:
 receive from a source UE associated with the current reference signal,   wherein the one or more processors, to extend the time window, are configured to extend the time window based at least in part on a data connection with the source UE.   
     
     
         9 . The apparatus of  claim 1 , wherein the current reference signal comprises a sidelink synchronization signal (SLSS). 
     
     
         10 . The apparatus of  claim 1 , wherein the search comprises an asynchronous SyncRef UE search or a SyncRef UE search without SLSS timing awareness. 
     
     
         11 . A method of wireless communication performed by a user equipment (UE), comprising:
 determining, periodically, at least one metric associated with a current reference signal on a sidelink; and   extending a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric.   
     
     
         12 . The method of  claim 11 , wherein the time window is extended as a function of a discontinuous reception (DRx) cycle associated with the UE. 
     
     
         13 . The method of  claim 11 , wherein the time window is extended for a preconfigured amount of time. 
     
     
         14 . The method of  claim 11 , wherein extending the time window comprises refraining from performing the search. 
     
     
         15 . The method of  claim 11 , wherein the at least one metric comprises a reference signal received power (RSRP) associated with the current reference signal, an RSRP variation associated with the current reference signal, an RSRP trend associated with the current reference signal, a reference signal received quality (RSRQ) associated with the current reference signal, or a combination thereof. 
     
     
         16 . The method of  claim 15 , wherein extending the time window comprises extending the time window based on:
 the RSRP associated with the current reference signal satisfying an RSRP threshold;   the RSRP variation associated with the current reference signal satisfying a variation threshold;   the RSRQ associated with the current reference signal satisfying an RSRQ threshold;   a direction of the RSRP trend associated with the current reference signal satisfying a trend threshold; or   a combination thereof.   
     
     
         17 . The method of  claim 11 , further comprising:
 transmitting to a source UE associated with the current reference signal,   wherein extending the time window comprises extending the time window based at least in part on a data connection with the source UE.   
     
     
         18 . The method of  claim 11 , further comprising:
 receiving from a source UE associated with the current reference signal,   wherein extending the time window comprises extending the time window based at least in part on a data connection with the source UE.   
     
     
         19 . The method of  claim 11 , wherein the current reference signal comprises a sidelink synchronization signal (SLSS). 
     
     
         20 . The method of  claim 11 , wherein the search comprises an asynchronous SyncRef UE search or a SyncRef UE search without SLSS timing awareness. 
     
     
         21 . A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising:
 one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the UE to:
 determine, periodically, at least one metric associated with a current reference signal on a sidelink; and 
 extend a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric. 
   
     
     
         22 . The non-transitory computer-readable medium of  claim 21 , wherein the time window is extended as a function of a discontinuous reception (DRx) cycle associated with the UE. 
     
     
         23 . The non-transitory computer-readable medium of  claim 21 , wherein the one or more instructions, that cause the UE to extend the time window, cause the UE to refrain from performing the search. 
     
     
         24 . The non-transitory computer-readable medium of  claim 21 , wherein the at least one metric comprises a reference signal received power (RSRP) associated with the current reference signal, an RSRP variation associated with the current reference signal, an RSRP trend associated with the current reference signal, a reference signal received quality (RSRQ) associated with the current reference signal, or a combination thereof. 
     
     
         25 . The non-transitory computer-readable medium of  claim 24 , wherein the one or more instructions, that cause the UE to extend the time window, cause the UE to extend the time window based on:
 the RSRP associated with the current reference signal satisfying an RSRP threshold;   the RSRP variation associated with the current reference signal satisfying a variation threshold;   the RSRQ associated with the current reference signal satisfying an RSRQ threshold;   a direction of the RSRP trend associated with the current reference signal satisfying a trend threshold; or   a combination thereof.   
     
     
         26 . The non-transitory computer-readable medium of  claim 21 , wherein the one or more instructions further cause the UE to:
 transmit to a source UE associated with the current reference signal,   wherein the one or more instructions, that cause the UE to extend the time window, cause the UE to extend the time window based at least in part on a data connection with the source UE.   
     
     
         27 . The non-transitory computer-readable medium of  claim 21 , wherein the one or more instructions further cause the UE to:
 receive from a source UE associated with the current reference signal,   wherein the one or more instructions, that cause the UE to extend the time window, cause the UE to extend the time window based at least in part on a data connection with the source UE.   
     
     
         28 . The non-transitory computer-readable medium of  claim 21 , wherein the current reference signal comprises a sidelink synchronization signal (SLSS). 
     
     
         29 . The non-transitory computer-readable medium of  claim 21 , wherein the search comprises an asynchronous SyncRef UE search or a SyncRef UE search without SLSS timing awareness. 
     
     
         30 . An apparatus for wireless communication, comprising:
 means for determining, periodically, at least one metric associated with a current reference signal on a sidelink; and   means for extending a time window allowed for a search for a new reference signal on the sidelink based at least in part on the at least one metric.